In recent years, there has been an increasing demand in the field of mobile data terminal devices such as cellular phones and personal digital assistants (PDAs) for a display device with a larger display area occupying a display surface in area ratio in terms of performance and design, etc. For example, there have been proposed display devices which realize a further narrow frame.
Conventionally, the structure where a driver is mounted on a periphery of a display area of a substrate containing electrodes has been known. In a display device with a mount system on which such a driver is mounted, a flexible printed circuit board (FPC) is used as a wiring board for inputting an input signal and voltage to the driver. In order to achieve an improvement in the yield and narrowing of the frame, there have been studies to develop a method of electrically connecting an interconnect formed on a lower surface side of an array substrate with a driver formed on an upper surface side thereof via a contact hole made through the array substrate without using an FPC or the like.